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Kudos for the frame review. Understanding the limitations that frames handle differently for riders of greater or less weight then the range they were designed for and wildly differing opinions on what a good frame is. Carbon wheel review..... Not so much. Important issues were left out IMO and trivial issue ( hub noise for example) received to much weight. Having owned or tried all the wheels tested I'm at a loss to understand VN's conclusions. Maybe it's just me?

Problem is if the fit isn't absolutely dialed in each case, body position differences can dominate.

It would be like trying to measure the benefit of 100 grams saved: you'll never see it in real world data.

But I like your idea!

P.S. My big issue with their aero wheel tests was they had two parameters devoted to weight: rotational inertia and actual weight, and one devoted to aerodynamics, and each was rated with equal weight. Since translational inertia is always a larger impediment to acceleration than rotational inertia (except on a trainer) and since it also applies to climbing power, obviously total weight is much more important than rotational inertia, and for aero wheels both are much less important than aerodynamics.

This frame test, with the exception of the lack of water bottle, was much better.

funhog1 wrote:I'm wondering......

VNTech........

as it's too daunting of a task for my schedule......

if you guys would be interested in having a clever VN intern collect/collate data for some regression analysis?

saaaaay actual real world road race results to attempt to figure out the measurable benefit (if any) of riding an aero frame in a road race?

I think some analysis may be achievable. For example use RA in an attempt to look for correlations between the average speed of the peloton increasing over time and technology changes within the industry and then within that frame start to look for any benefit to riding an aero bike in a road race.

If VNTech has the time maybe something would turn up.

Just for fun?

Accounting for changes in road surfaces and tire technology alone would be quite the thing......

Bicycle Quarterly did a similar analysis to look at the effect of the derailleur on European race speeds. Even with as drastic a change as that, the "signal" was hard to see above the "noise". In particular there's always other things changing, like anti-doping enforcement.

The contrast with the Tour results really couldn't be more striking. There, the Cervelo was actually slower than the Cannondale System 6 at zero yaw.

Tour reported a typical CdA for zero yaw with rider is 0.31. So a difference of 0.023 (the Cervelo to the "standard bike") is around 7.4% of total wind power. At 40 kph the power difference is 18.6 watts out of 250 watts. At this speed, 33 watts is a typical rolling resistance power (12% of total). Thus, a 7.4% reduction in wind resistance power is around a 2.3% savings in total speed: 85 seconds / hour.

VeloNews claimed more than that: 128 seconds. But they average over yaw angles from -20 to +20 degrees.

I think omitting the rider should overestimate the aero benefit somewhat, so I'd view the VeloNews results as an upper bound on possible savings.

Perhaps the above reflects the results of actually including cables and housing in the testing? The cable runs are MUCH less exposed on those aero bikes than any "standard bike"

Good call. Also the rider's legs tend to nullify the advantage of an aero seatpost, which gets clean air in the VeloNews test (and has nothing trailing it, so if air can get by the seatpost intact, it's clear).

A waterbottle would have neutralized a nice section of the downtube, but both tests make that mistake.

btw everyone should look at this article. if you disregard the cervelop4 great numbers at 0-5 yaw(they using uci-illegal ventus bar) all the super tt bike are very close. notice the difference a round water bottle makes to the drag numbers.

spartan wrote:btw everyone should look at this article. if you disregard the cervelop4 great numbers at 0-5 yaw(they using uci-illegal ventus bar) all the super tt bike are very close. notice the difference a round water bottle makes to the drag numbers.

Well for what it's worth, the Trek's bars are also UCI illegal (though not 22:1 aspect ratio illegal). And the Giant and Specialized both have their UCI illegal nosecones attached. Of course the test was for triathletes who buy 95% of those bikes, and don't care about UCI legality.

If a company is going to make an integrated front end with their own proprietary bars like Trek, Giant, and Specialized, or semi-integrated with it's own proprietary stem that accepts bars without an integrated stem like the Scott (note: they even used the USE Tula for the Scott, which is supposed to be an incredibly fast bar as well) then I think it's a fair test. The moduability of the P4 is one thing it has going for it, you can use all of the most aero equipment without resorting to jury rigged setups, and questionable integration issues.

They're all very close, and once you get the rider on there, the differences are so minute.

Interesting aspect of this test: how much better the Felt did with the Zipp 440 than it had done with the "stock" Mavic Cosmics.

Another interesting point: it is mentioned the Felt may have suffered at zero yaw due to its heavily padded handlebar tape and fat handlebars. And I'd thought Oval Concepts claim that 26 mm bars had superior aerodynamics was excessive. It was surprising to me the Felt did worse than the Ridley at zero yaw, despite a slimmer head tube.

And then the apparent importance of internal cables. I like the point which was made here that this may help explain why the Cervelo did so much better at zero yaw here relative to the "control" bike than it had with the Tour test: in the Tour test there were no cables to hide.